ARM: fix multiplatform allmodcompile

ARM: fix multiplatform allmodcompile

Commit 68f3b875f7848f5304472184a4634148c5330cbd
"ARM: integrator: make the Integrator multiplatform"
broke allmodconfig like this:

>> arch/arm/include/asm/cmpxchg.h:114:2: error: #error
"SMP is not supported on this platform"
(etc)

This is due to the fact that as we turned on multiplatform
for the Integrator, this enabled a lot of non-applicable
CPU's to be selected for its multiplatform images, due to
a lot of "depends on ARCH_INTEGRATOR" restrictions in
arch/arm/mm/Kconfig for the different ARM CPU types.

Fix this by restricting the CPU selections to respective
multiplatform config, which now becomes a subset of the
possible Integrator configurations, or alternatively the
non-multiplatform config plus ARCH_INTEGRATOR, i.e.:

if (!ARCH_MULTIPLATFORM || ARCH_MULTI_Vx) &&
   (ARCH_INTEGRATOR || ARCH_FOO ...)

Since the Integrator has been converted to multiplatform,
this will often take the short form:

if (ARCH_MULTI_Vx && ARCH_INTEGRATOR)

If no other non-multiplatform platforms are elegible.

Reported-by: Build bot for Mark Brown <broonie@kernel.org>
Reported-by: Kbuild test robot <fengguang.wu@intel.com>
Suggested-by: Russell King <linux@arm.linux.org.uk>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>